CHEMISTRY PLEASE HELP? Intermolecular forces.. Explain th differenced in structure and bonding of three pairs of molecules??

Question

Account for the differences in properties given in the table below in terms of the differences in structure and bonding in each of the following pairs.

 

Substance    Bond Length

 

F2                1.42

Br2               2.28

N2                 1.09

 

 

a. F2 and Br2

 

b. F2 and N2

 

Can you please help me!? I am so lost and I would genuinely appreciate the help!

Answer 1

Hello Angelica,

 

All three of your molecules are diatomic (meaning they are made up of 2 atoms). 

 

There are a few things that affect bond length between two atoms: 

• How large are the atoms? Larger atoms have more shells of electrons and thus will span a greater distance from one another the bond must cover. 
• How many covalent bonds are shared? A single bond holds pretty tightly, a double bond is even stronger, and a triple bond is very strong. These strengths pull the atoms in closer and thus decrease the bond length. This is called multiplicity of bonds or how many bonds exist between the atoms.
• Bond strength also affects the bond length. The stronger the bond, the shorter the length. 

 

Atoms bond with the goal of becoming more stable. If an atom losing a bond will cause it to be unstable, it will hold on to it very tightly. 

 

Let's look at your examples: 

 

F₂ 1.42 - Diatomic, Fluorine's atomic radius: 42 pm, held together by a single covalent bond
Br₂ 2.28 - Diatomic, Bromine's atomic radius: 94 pm, held together by a single covalent bond
N₂ 1.09 - Diatomic, Nitrogen's atomic radius: 56 pm, held together by a triple covalent bond

Now, look through this information and see which of the three factors that affect bond length apply. 

 

Need more help? Let's meet online via Wyzant sometime, I'd be happy to help you master this topic.